Sanitizing compositions and methods

ABSTRACT

A hydrophobic bleaching agent comprising a peroxyacid having a carbon chain of at least 9 carbon atoms is used for the reduction of the activity of micro-organisms that have a cell wall containing high levels of peptidoglycan. Such micro-organisms include yeast and gram positive bacteria.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of PCT International ApplicationSerial No. PCT/US99/21166, filed Sep. 10, 1999, which in turn claimspriority to GB 9819979.7, filed Sep. 15, 1998.

TECHNICAL FIELD

This invention provides methods for improved sanitisation and the use ofspecific sanitising compositions.

BACKGROUND TO THE INVENTION

Traditionally, hard-surface cleaners contain bleach as cleaning agentand as disinfectant. In particular, they contain high levels of chlorinebleach to achieve the required cleaning and disinfecting properties.

Research has shown that hydrogen peroxide bleach in laundry and dishwashing detergents also has a disinfecting action, see for example MBlaser et al. in: The journal of infectious diseases, vol 149,no.1,1984.

More recently, detergent manufacturers have become interested in thedisinfecting properties of these detergents. Various disclosuresdescribe bleach systems which provide both cleaning and disinfectingduring the laundering, for example DE 19616782, DE19605688, DE 19536082,WO9418297. Not all bleach systems which have disinfecting properties aresuitable for detergents: they are not always compatible with otherdetergent ingredients, such as enzymes, or the levels of bleach requiredto obtain disinfecting are too high and may damage the fabrics.

The inventors now have found that most bleach systems known in the art,including TAED, percarbonate and perborate bleaches, effectively killgram negative bacteria, but not effectively other micro-organisms, inparticular, gram all positive bacteria. Also, it has been found that theanti-bacterial activity of for example TAED is dependent on the pH,resulting in a strong reduction of anti- bacterial activity on grampositive bacteria at a alkaline pH, such as for example during washingconditions.

Many soils, including body soil, mainly contain micro-organisms otherthan gram negative bacteria, in particular, gram positive bacteria. Theinventors have found that detergents containing for example TAED and aperoxygen source do thus not effectively sanitise these types of soils,in particular at low temperatures as normally used by consumers duringlaundering, dish washing or other cleaning methods.

They have now found that specific hydrophobic bleaching agenteffectively inactivate micro-organisms including gram positive bacteria,such as Enterococcus hirae and Staphyloccocus aureus bacteria. Thus,when these specific hydrophobic bleaching agents are used in detergents,not only excellent stain removal of bleachable stains and soils isachieved but also sanitisation.

It is believed that the specific hydrophobic bleaching agent have animproved surface activity for the peptidoglycan in the cell walls of,for example, yeast and gram positive bacteria compared to hydrophilicbleaching agents. It is believed that these specific hydrophobic agentsthus penetrate and disrupt these cell walls more effectively than otherhydrophilic bleaching agents.

Since the specific hydrophobic bleaching agent is found to be veryeffective, a further benefit can be that reduced levels of bleach can beemployed.

Further improved sanitisation can be achieved when both hydrophilic andhydrophobic bleaching agents are employed, resulting in effectiveinactivation of both gram positive bacteria and gram negative bacteria.

SUMMARY OF THE INVENTION

The invention provides the use of a hydrophobic bleaching agentcomprising a peroxyacid having a carbon chain of at least 9 carbon atomsfor the reduction of the activity of micro-organism which have a cellwall which contain a high level of peptidoglycan.

When used herein, ‘high levels of peptidoglycan’ means that themicro-organisms have high levels of peptidoglycan, compared to gramnegative bacteria. The cell walls preferably comprise a layer whichpredominantly comprises peptidoglycan They include yeast and inparticular, gram positive bacteria.

When used herein, ‘reduction of the activity of the micro-organisms’includes a reduction of the activity as defined in the CEN methodprEN1276, 1993, (Comité Européen de Normalisation) and CEN method prEN1650. The reduction therein is preferably represented by a reduction ofmicro-organisms, preferably at least of 10⁵, more preferably at least10⁶ or even more for actaria, or at least 10⁴ or even at least 10⁵ foryeast.

The reduction of the activity of the micro-organisms when used hereinincludes the reduction of any of the processes conducted by themicro-organisms which have a cell wall including high levels ofpeptidoglycan, compared to gram negative bacteria., including secretionof products but preferably the growth of the micro-organisms.

The invention also provides a method for reduction of the activity ofmicro-organisms, or preferably gram positive bacteria comprising thesteps of contacting the micro-organism with an aqueous liquor comprisinga hydrophobic bleaching agent comprising a peroxyacid having a carbonchain of at least 9 carbon atoms at a level of at least 100 ppm in theliquor, per 10⁶ micro-organisms.

DETAILED DESCRIPTION OF THE INVENTION

Method and Use

The specific hydrophobic bleaching agents herein are used to reduce theactivity of specific micro-organisms which have high levels ofpeptidoglycan in the cell walls, including yeast and gram positivebacteria. In particular, this is done during a sanitisation process or acleaning process. Hereby, the bleaching agent can be contacted with thespecific micro-organisms in solid form, but preferably the bleachingagent is present in a liquor in contact with the micro-organisms.

The specific micro-organisms gram positive bacteria can be present onthe surfaces or fabrics to be cleaned and sanitised, for example on thefabrics to be cleaned in a dish washing process or laundry process. Thegram positive bacteria can also be present in the liquor used for thecleaning or sanitisation process or in the equipment used in theprocess, such as the washing machine.

The micro-organisms having cell walls comprising relatively high levelsof peptidoglycan, in particular the gram positive bacteria, can bepresent in soils present on these fabrics or surfaces, in particular inbody soils.

The amount of hydrophobic bleaching agent required to obtain effectivereduction of the activity of the specific micro-organisms, such as,yeast and gram positive bacteria depends on various factors, such as theamount of micro-organisms present, the conditions of the sanitisation orcleaning process, including the other compounds present, thetemperature.

It should be noted that the present hydrophobic bleaching agent may alsoreduce the activity of micro-organisms which do not comprise high levelsof peptidoglycan in their cell walls to a lesser extent, or lessefficiently, e.g. gram negative bacteria.

In the method of the invention, the liquor used preferably comprises atleast 100 ppm of the hydrophobic peroxyacid per 10⁶ micro-organisms,more preferably at least 200 ppm or even 250 ppm.

The reduction of the activity of the specific micro-organisms, having apeptidoglycan-containing cell walls can be determined by the Petrocciand Clarke method, as described in JOAC 1981, but is preferablydetermined for the purpose of this invention by the CEN method prEN1276,1993 for bacteria and CEN method prEN1650 for yeast.

Such a CEN method involves, for example, the preparation of grampositive bacterial inocula conform the DEN method, pages 7 and further,preparation of a solution comprising the hydrophobic bleaching agent ata level of about 250 ppm. conducting the test following the CEN method,incubation TSA plates for 24 hours at 36° C.; and subsequently countingof the bacteria colonies on the plates.

This is compared with the results of the reference and the reduction ofbacteria growth is calculated, for the defined contacting time.

Micro-Organisms

The specific micro-organisms herein comprise a cell wall which containcell walls with high levels of peptidoglycan. In particular, usefulherein are yeast and most preferably gram positive bacteria.

The gram positive bacteria are typically present in soils on the fabric,in particular body soils. Typical gram positive bacteria areEnterococcus hirae and Staphyloccocus aureus.

Hydrophobic Bleaching Agent

The hydrophobic bleaching agent herein comprises a peroxyacid having acarbon chain of at least 9 carbon atoms. The agent can be a preformedperoxyacid or it can be a compound which provides such a hydrophobicperoxyacid by a chemical reaction, such as the bleach precursorsdescribed herein. Also mixtures of these precursor and preformedhydrophobic peroxyacid can be used.

Preferably the hydrophobic bleaching agent comprises a hydrogen peroxidesource and a hydrophobic peroxyacid bleach precursor. The production ofthe hydrophobic peroxyacid occurs by an in situ reaction of theprecursor with a source of hydrogen peroxide source. Preferred sourcesof hydrogen peroxide include inorganic perhydrate bleaches, describedhereinafter.

The hydrophobic peroxyacid contains at least 9 carbon atoms, mostpreferably at least 11 carbon atoms. In a preferred aspect theperoxyacid has an alkyl chain, containing at least 8 or 9 or even atleast 10 carbon atoms. Preferably, the peroxy acid but in particular theperoxy acid precursor comprises a N-acyl group.

Preferably, the hydrophobic peroxyacid bleaching agent in a solution isused to reduce the activity of gram positive bacteria, in particular indish washing or laundry process such that the solution comprises atleast 100 ppm of the peroxyacid or peroxyacid precursor per 10⁶bacteria.

The precursors have a structure

hereinafter L is a leaving group which must be sufficiently reactive forthe perhydrolysis reaction to occur within the optimum time frame (e.g.,a wash cycle). However, if L is too reactive, this activator will bedifficult to stabilize for use in a bleaching composition.

The L groups are preferably selected from the group consisting of:

also suitable as L group may be

and mixtures thereof, wherein R¹ is an alkyl, aryl, or alkaryl groupcontaining from 1 to 14 carbon atoms, R³ is an alkyl chain containingfrom 1 to 8 carbon atoms, R⁴ is H or R³, and Y is H or a solubilizinggroup. Any of R¹, R³ and R⁴ may be substituted by essentially anyfunctional group including, for example alkyl, hydroxy, alkoxy, halogen,amine, nitrosyl, amide and ammonium or alkyl ammmonium groups

The preferred solubilizing groups are —SO₃ ⁻M⁺, —CO₂ ⁻M⁺, SO₄ ⁻M⁺,—N⁺(R³)₄X⁻ and O←N(R³)₃ and most preferably —SO₃ ⁻M⁺ and —CO₂ ⁻M³⁰

wherein R³ is an alkyl chain containing from 1 to 4 carbon atoms, M is acation which provides solubility to the bleach activator and X is ananion which provides solubility to the bleach activator. Preferably, Mis an alkali metal, ammonium or substitutedammonium cation, with sodiumand potassium being most preferred, and X is a halide, hydroxide,methylsulfate or acetate anion.

Suitable hydrophobic peroxyacid bleach precursors herein typicallycontain one or more N-acyl groups, which precursors can be selected froma wide range of classes. Suitable classes include imides, lactams andacylated derivatives of imidazoles. Suitable N-acylated precursorcompounds of the lactam class disclosed generally in GB-A-955735.Preferred materials of this class comprise the caprolactams.

Highly preferred peroxyacid precursors are amide substituted alkylperoxyacid precursor compounds, including those of the following generalformulae:

wherein R¹ is an aryl or alkaryl group with from about 1 to about 14carbon atoms, R² is an alkylene, arylene, and alkarylene groupcontaining from about 1 to 14 carbon atoms, and R⁵ is H or an alkyl,aryl, or alkaryl group containing 1 to 10 carbon atoms and L can beessentially any leaving group. R¹ preferably contains from about 6 to 12carbon atoms. R² preferably contains from about 4 to 8 carbon atoms. R¹may be straight chain or branched alkyl, substituted aryl or alkylarylcontaining branching, substitution, or both and may be sourced fromeither synthetic sources or natural sources including for example,tallow fat. Analogous structural variations are permissible for R². R²can include alkyl, aryl, wherein said R² may also contain halogen,nitrogen, sulphur and other typical substituent groups or organiccompounds. R⁵ is preferably H or methyl. R¹ and R⁵ should not containmore than 18 carbon atoms total. Amide substituted bleach activatorcompounds of this type are described in EP-A-0170386.

Preferred examples of bleach precursors of this type include amidesubstituted peroxyacid precursor compounds selected from(6-octanamido-caproyl)oxybenzenesulfonate, (6-decanamido-caproyl)oxybenzene-sulfonate, and the highly preferred (6-nonanamidocaproyl)oxybenzene sulfonate, and mixtures thereof as described in EP-A-0170386.

A preferred class of hydrophobic organic :peroxyacid compounds are theamide substituted compounds of the following general formulae:

wherein R¹ is an aryl or alkaryl group with from about 1 to about 14carbon atoms, R² is an alkylene, arylene, and alkarylene groupcontaining from about 1 to 14 carbon atoms, and R⁵ is H or an alkyl,aryl, or alkaryl group containing 1 to 10 carbon atoms, provided that atleast 9 carbon atoms are present. R¹ preferably contains from about 6 to12 carbon atoms, preferably 9 to 12. R² preferably contains from about 4to 8 carbon atoms. R¹ may be straight chain or branched alkyl,substituted aryl or alkylaryl containing branching, substitution, orboth and may be sourced from either synthetic sources or natural sourcesincluding for example, tallow fat. Analogous structural variations arepermissible for R². R² can include alkyl, aryl, wherein said R² may alsocontain halogen, nitrogen, sulphur and other typical substituent groupsor organic compounds. R⁵ is preferably H or methyl. R¹ and R⁵ should notcontain more than 18 carbon atoms total. Amide substituted bleachactivator compounds of this type are described in EP-A-0170386. Suitableexamples, of this class of agents include (6-octylamino)-6-oxo-caproicacid, (6-nonylamino)-6-oxo-caproic acid, (6-decylamino)-6-oxo-caproicacid, magnesium monoperoxyphthalate hexahydrate, the magnesium salt ofmetachloro perbenzoic acid, 4-nonylamino-4-oxoperoxybutyric acid anddiperoxydodecanedioic acid. Such bleaching agents are disclosed in U.S.Pat. Nos. 4,483,781, 4,634,551, EP 0,133,354, U.S. Pat. No. 4,412,934and EP 0,170,386. A preferred hydrophobic preformed peroxyacid bleachcompound for the purpose of the invention is monononylamidoperoxycarboxylic acid.

Other suitable organic peroxyacids include diamino peroxyacids, whichare disclosed in WO 95/03275, with the following general formula:

wherein:

R is selected from the group consisting of C₁-C₁₂ alkylene, C₅-C₁₂cycloalkylene, C₆-C₁₂ arylene and radical combinations thereof;

R¹ and R² are independently selected from the group consisting of H,C₁-C₁₆ alkyl and C₆-C₁₂ aryl radicals and a radical that can form aC₃-C₁₂ ring together with R³ and both nitrogens; R³ is selected from thegroup consisting of C₁-C₁₂ alkylene, C₅-C₁₂ cycloalkylene and C₆-C₁₂arylene radicals; n and n′ each are an integer chosen such that the sumthereof is 1; m and m′ each are an integer chosen such that the sumthereof is 1;

and M is selected from the group consisting of H, alkali metal, alkalineearth metal, ammonium, alkanolammonium cations and radicals andcombinations thereof; and provided that the peroxyacid comprises atleast 9 carbon atoms;

Other suitable organic peroxyacids are include the amido peroxyacidswhich are disclosed in WO 95/16673, with the following generalstructure:

X—Ar—CO—NY—R(Z)—CO—OOH

in which X represents hydrogen or a compatible substituent, Ar is anaryl group, R represents (CH₂)_(n) in which n=2 or 3, and Y and Z eachrepresent independently a substituent selected from hydrogen or an alkylor aryl or alkaryl group or an aryl group substituted by a compatiblesubstituent provided that at least one of Y and Z is not hydrogen ifn=3. The substituent X on the benzene nucleus is preferably a hydrogenor a meta or para substituent, selected from the group comprisinghalogen, typically chlorine atom, or some other non-releasednon-interfering species such as an alkyl group, conveniently up to C6for example a methyl, ethyl or propyl group. Alternatively, X canrepresent a second amido-percarboxylic acid substituent of formula:

—CO—NY—R(Z)—CO—OOH

in which R, Y, Z and n are as defined above.

MOOC—R¹CO—NR²—R³—NR⁴—CO—R⁵COOOM

wherein R¹ is selected from the group consisting of C₁-C₁₂ alkylene,C₅-C₁₂ cycloalkylene, C₆-C₁₂ arylene and radical combinations thereof; R

Hydrogen Peroxide Source

Inorganic perhydrate salts are a preferred source of hydrogen peroxide.

Examples of inorganic perhydrate salts include perborate, percarbonate,perphosphate, persulfate and persilicate salts. The inorganic perhydratesalts are normally the alkali metal salts. The inorganic perhydrate saltmay be included as the crystalline solid without additional protection.For certain perhydrate salts however, the preferred executions of suchgranular compositions utilize a coated form of the material whichprovides better storage stability for the perhydrate salt in thegranular product. Suitable coatings comprise inorganic salts such asalkali metal silicate, carbonate or borate salts or mixtures thereof, ororganic materials such as waxes, oils, or fatty soaps.

Sodium perborate is a preferred perhydrate salt and can be in the formof the monohydrate of nominal formula NaBO₂H₂O₂ or the tetrahydrateNaBO₂H₂O₂.3H₂O.

Alkali metal percarbonates, particularly sodium percarbonate arepreferred perhydrates herein. Sodium percarbonate is an additioncompound having a formula corresponding to 2Na₂CO₃.3H₂O₂, and isavailable commercially as a crystalline solid.

Potassium peroxymonopersulfate is another inorganic perhydrate salt ofuse in the detergent compositions herein.

Hydrophilic Bleach

In the method herein or in the compositions herein, a hydrophilicbleaching agent may be present in addition to the hydrophobic bleachingagent. A suitable hydrophilic bleaching agent is TAED.

Preferably the hydrophilic bleaching agent is present at a ratio to thehydrophobic peroxyacid from 1:5 to 5:1, more preferably from 1:3 to 3:1,most preferably from 1:2 to 2:1

Detergent Compositions

The hydrophobic bleaching agent herein is preferably present in adetergent composition, when used to reduce the activity ofmicro-organisms.

Thus, the reduction of the activity preferably takes place during acleaning method, preferably a automatic or hand laundry or dish washingmethod, in particularly at low temperatures up to 60° C. or even 45° C.or even 30° C.

When the hydrophobic peroxyacid bleaching agent contains a peroxyacidbleach precursor, the precursor is typically present at a level of from0.05% to 20% by, more preferably from 0.5% to 10% by weight, mostpreferably from 1% to 7% by weight of the composition. When thehydrophobic peroxyacid bleaching agent contains a preformed hydrophobicperoxyacid, the preformed peroxyacid is typically present at a level offrom 0.05% to 15% by weight, more preferably from 1% to 10% by weight ofthe composition.

The hydrogen peroxide sources, when present, are preferably incorporatedin the compositions herein the form of the alkali metal, preferablysodium salt at a level of from 1% to 40% by weight, more preferably from2% to 30% by weight and most preferably from 5% to 25% by weight of thecompositions.

The hydrophilic bleach, when present, may preferably be present at alevel of from 0.5% to 12% by weight of the composition.

The detergent compositions herein may comprise any additionalingredients, commonly employed in detergents. The precise nature ofthese additional components, and levels of incorporation thereof willdepend on the physical form of the composition and the precise nature ofthe washing operation for which it is to be used.

The compositions preferably contain one or more additional detergentcomponents selected from surfactants, effervescence sources, bleachcatalysts, chelating agnets, bleach stabilisers, alkalinity systems,builders, phosphate-containing builders, organic polymeric compounds,enzymes, suds suppressors, lime soap, dispersants, soil suspension andanti-redeposition agents, soil releasing agents, perfumes, dyes, dyedspeckles, brighteners, photobleaching agents and additional corrosioninhibitors.

Laundry Washing Method

Machine laundry methods herein typically comprise treating soiledlaundry with an aqueous wash solution in a washing machine havingdissolved or dispensed therein an effective amount of a machine laundrydetergent composition containing the hydrophobic bleaching agent inaccord with the invention. By an effective amount of the detergentcomposition it is meant from 10 g to 300 g of product dissolved ordispersed in a wash solution of volume from 5 to 65 litres, as aretypical product dosages and wash solution volumes commonly employed inconventional machine laundry methods. Dosage is dependent upon theparticular conditions such as water hardness and degree of soiling ofthe soiled laundry. The pH of the washing liquor is typically above 7,preferably above 8.5 or above 9 or even 9.5.

The detergent composition may be dispensed for example, from the drawerdispenser of a washing machine or may be sprinkled over the soiledlaundry placed in the machine.

In one use aspect a dispensing device is employed in the washing method.Especially preferred dispensing devices for use with the composition ofthe invention have been described in the following patents; GB-B-2, 157,717, GB-B-2, 157, 718, EP-A-0201376, EP-A-0288345 and EP-A-0288346. Anarticle by J.Bland published in Manufacturing Chemist, November 1989,pages 41-46 also describes especially preferred dispensing devices foruse with granular laundry products which are of a type commonly know asthe “granulette”. Another preferred dispensing device for use with thecompositions of this invention is disclosed in PCT Patent ApplicationNo. WO94/11562.

Machine Dishwashing Method

Any suitable methods for machine dishwashing or cleaning soiledtableware.

A preferred machine dishwashing method comprises treating soiledarticles selected from crockery, glassware, hollowware, silverware andcutlery and mixtures thereof, with an aqueous liquid having dissolved ordispensed therein an effective amount of a machine dishwashingcomposition herein. By an effective amount of the machine dishwashingcomposition it is meant from 8 g to 60 g of product dissolved ordispersed in a wash solution of volume from 3 to 10 litres, as aretypical product dosages and wash solution volumes commonly employed inconventional machine dishwashing methods.

What is claimed is:
 1. A method of reducing of the activity ofmicro-organisms containing a cell wall that contains high levels ofpeptidoglycan, said method comprising the steps of contacting saidmicro-organisms with an aqueous liquor having a pH greater than 8.5,said liquor comprising a hydrophobic bleaching agent comprising aperoxyacid having a carbon chain of at least 9 carbon atoms.
 2. A methodaccording to claim 1 wherein said peroxyacid having a carbon chain of atleast 9 carbon atoms is present in said liquor at a level of at least100 ppm per 10⁶ micro-organism.
 3. A method according to claim 2,wherein said liquor comprises a detergent composition comprising ahydrophobic peroxyacid precursor, said hydrophobic peroxyacid precursorbeing present in said detergent composition at a level of at least 1% byweight of said detergent composition.
 4. A method according to claim 2wherein said micro-organisms are selected from the group consisting ofyeast, gram positive bacteria and mixtures thereof.
 5. A methodaccording to claim 2, wherein said contacted micro-organisms arecontacted with said liquor while said organisms are present on a fabric.6. A method according to claim 2, wherein said contacted micro-organismsare contacted with said liquor while said organisms are present on ahard surface.
 7. A method according to claim 3, wherein said hydrophobicperoxyacid precursor is present in said detergent composition at a levelof from 1% by weight to 10% by weight of said detergent composition. 8.A method according to claim 7 wherein said micro-organisms are selectedfrom the group consisting of yeast, gram positive bacteria and mixturesthereof.
 9. A method according to claim 8, wherein said contactedmicro-organisms are contacted with said liquor while said organisms arepresent on a fabric.
 10. A method according to claim 8, wherein saidcontacted micro-organisms are contacted with said liquor while saidorganisms are present on a hard surface.
 11. A method according to claim2, wherein said liquor comprises a hydrogen peroxide source.
 12. Amethod according to claim 2, wherein said peroxyacid comprises an N-acylgroup.
 13. A method according to claim 2, wherein said hydrophobicbleaching agent comprises a 6-(nonanamidocaproyl)oxybenzene sulphonatesalt.
 14. A method of reducing of the activity of micro-organismsselected from the group consisting of yeast, gram positive bacteria,gram negative bacteria and mixtures thereof, comprising the steps ofcontacting said micro-organisms with an aqueous liquor having a pHgreater than 8.5, said liquor comprising a hydrophobic bleaching agentcomprising a peroxyacid having a carbon chain of at least 9 carbon atomsand a hydrophilic bleaching agent.
 15. A method according to claim 14wherein said peroxyacid having a carbon chain of at least 9 carbon atomsis present in said liquor at a level of at least 100 ppm per 10⁶micro-organism.
 16. A method according to claim 14, wherein saidhydrophilic bleaching agent comprises TAED.